Computer user behavior and the stability of network communication channels over which computers communicate are often unpredictable. Networked users on occasion change computing environments while forgetting to, or without having the opportunity to, fully save their work product or to shut down their systems. In other cases, communication channels unexpectedly fail or computers crash, which can result in the loss of work product, if the session is not restored or terminated gracefully.
Failing to gracefully cease usage of a shared network resource can lead to a variety of difficulties for networked application users. Many software applications restrict other users' ability to use shared network resources, such as data files, while a resource is in use, usually to prevent conflicting manipulation of the resource. For example, documents can be “checked out” while being edited by a user so that another user does not attempt to simultaneously edit the document, or use a stale copy of the document. If a user checks out a document while working from one computer, and then leaves the computer without subsequently “checking it in,” the document can be rendered inaccessible to other users, without intervention by an administrator. And typically, upon such intervention, the changes made to the document are lost.